Leaving the European Union could boost the British economy by delivering jobs, boosting prosperity and galvanising the ‘single market’. According to a top Tory all these benefits would naturally accrue and not necessarily be the negative ‘leap in the dark’ opponents make out.

Speaking after the Bank of England accidentally emailed details of its secret plan to investigate the impact of quitting the EU, Owen Paterson, the former Conservative Cabinet minister, said suggesting that the banking industry would be threatened by the move was wrong.

He told Radio 4’s Today Programme Brexit did not mean quitting the European Economic Area, made up of the 28 countries of the EU along with Iceland, Norway and Switzerland. It did not even involve splitting the European single market, which Britain voted to join in the last referendum in 1975. He said:

“The European Union is a political construct, and the jobs and the prosperity are delivered by the market. We have an opportunity to get back to the arrangement we voted to join in 1975 and … very importantly we can completely regalvanise the single market in areas such as services which we completely need.

“Most importantly we would get our seat back on the global bodies which decide regulation. There is absolutely a very clear option for us to play a major role in the single market and be very significant members of the EEA without participating in the political and judicial arrangements of the EU. And it is very important to get that message across. I see a really optimistic, positive future for us.”

Mr Paterson, the former Environment Secretary, said Britain was being forced out of the EU after being left behind by the Eurozone countries as they effectively formed a “new country” by framing policies to support bankrupt economies such as Greece.

“We can never go there. We’re never, ever going to join the euro,” he said.

Mr Paterson said while it was legitimate for the Bank of England to explore the impact of leaving the EU, it should not view quitting as “a leap into some terrible black abyss”.

“There are various options which can deliver prosperity, increase jobs … which is as members of the single market. It isn’t either remain in the European Union or leap into the dark. There are other options.”